First let’s define both grounding and bonding in lay terms. Bonding is electrically connecting metal objects together that were not intended to carry electricity in the pool system. Grounding is bonding that system to the earth.
Bonding keeps the metal objects at the same potential voltage, and when there is no difference of potential, there is no current flow. An example is a bird on an electrical wire/powerline. If the bird touches only that wire, it is at the same potential as the wire, and thus it will not be affected. However, if the power line were to be low enough to the ground and the bird large enough to touch the ground while also touching the wire, there would now be a difference of potential in the power line with a few thousand volts and the ground with almost no volts. This would electrocute the bird as it now makes a path for the electricity to flow.
By Code, all metal objects in the pool area are supposed to be bonded, including the pump. The pump is tied back to the circuit breaker panel, which is tied back to the utility system’s neutral line. Therefore, whatever voltage exists on the utility system neutral is now what exists on the pool system, and they both increase and decrease together.
The Importance of Proper Equipotential Bonding in Pool Decks
A colleague at an electric research institute painted the picture this way. Think of the pool, the deck, rails, and ladders as one system, and that system floats in the air. As long as you are standing on the system, you will be fine. Even if that system is 200 feet in the air, you will be safe if you don’t step off that system and fall to the ground. However, if part of that system is not bonded and not at the same potential voltage as the ground around it, it will be similar to a hole and you will fall through the hole. Similarly with the deck, the deck needs to be bonded also to extend the “system” out a few feet from the water to protect wet swimmers from “falling off” the system. This is why it is so important to use our EquiBond equipotential copper bonding grids or encase steel rebar in concrete in the deck, to provide the equipotential plane and extend the system out a few feet from the water.
Water makes a concrete or paver deck highly conductive, and because the purpose of the deck is for swimmers to enter and exit the water, it gets wet and highly conductive. Bonding steel rebar in the pool wall and the metal objects in the area creates an equipotential bonding plane. The wet and conductive deck next to the water is why it is so important to extend the equipotential bonding plane at least 3 feet out from the water. The further from the water, the less conductive the deck and the drier the swimmer becomes. Similar to the drier/less conductive deck acting like a ramp from the elevated pool system sloping to the ground. This way of thinking about a pool system may lead to better understanding of the importance of proper bonding. For more information on our equipotential bonding grids, call 919-781-3411 or email [email protected], and ensure you have Code Compliant installations that increase your profits and keep swimmers safe!